Telegraph exchange system



Oct. 23, 1945;

4E. A. DEMONET ET AL TELEGRAPH EXCHANGE SYSTEM 7 Filed Sept. 25, 1941 2 Sheets-Sheet. 1

29 2.5 025555. uhozum -To me. 2

INVENTORS E.A.DEMONET BY f7? LANTON ATTORNEY Oct. 23, 1945. E. A. I'DEMONET ET AL TELEGRAPH EXCHANGE SYSTEM 2 Sheets-Sheet 2 Filed Se t 25, 1941 4 INVENTORS E A DEMON .rDO omuk U072.

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Patented Oct. 23, 1945 OFFICE TELEGRAPH EXCHANGE SYSTEM Eugene A. Demonet, Short Hills, N. J., and William B. Blanton, Merrick, N. Y., assignors to The Western Union Telegraph Company, Ne York, N. 1 a corporation of New York Application September 23, 1941, Serial No. 411,948

9 Claims. l Cl. 1'784) This invention relates to telegraph exchange systems and more particularly to systems involving a main office and a plurality of branch offices or teleprinter stations, each connected with the main oflice.

One object of the invention is to simplify the handling of messages to be sent from branch offices over a trunk circuit terminating at a'local main office.

Another object of the invention is to provide an improved switching system arranged to interconnect a teleprinter at a main office to selected line circuits and also to interconnect printing telegraph equipment at a plurality of branch ofiices adjacent said main oflice to outgoing trunks terminating in said main office.

A still further object of the invention is to provide an improved arrangement for operating calling and supervisory signals in a system of the character described over the line circuit utilized for telegraphic communication.

Other objects and advantages of the invention will become apparent from the following description of the preferred embodiment thereof shown on the accompanying drawings, wherein:

Figs. 1 and 2 taken together form a complete diagram of a telegraph exchange system including a main oflice, nearby branch oifices or teleprinter stations, and a plurality of inter-city trunks or channels to which both the main office and the branch office printing telegraph equipment may be connected.

In accordance with the invention, a plurality of branch telegraph ofiices are normally connected to signal storage equipment at the main ofiice associated with one or more outgoing telegraph lines or channels, usually inter-city trunks. rdinary messages transmitted from the branch offices are stored in the storage equipment and repeated over an associated line or channel without manual handling or switching of the line circuit. If, however, one of the branch oflices desires to communicate with the main ofiice or another local station, a signal is operated over the branch ofice line circuit to indicate that a connection is desired with the main office or said local station, and the attendant at the main oflice answers the call or switches it to the desired station. The

switchboard or equivalent switching equipment at the main office is arranged to extend any call, regardless of origin, to the desired bran'choflice line. Calling and supervisory signals are controlled over the branch office line circuits to initiate a call, to indicate the setting up of the,

connection at the switchboard, and to prevent interference between different calls.

Referring to the drawings, the printer I0 at station No. l'represents one of a plurality of branch ofiices or teleprinter stations each connected by an individual line circuit similar to the line Ll to the main oflice shown in Figs. 1 and 2. It is to be understood that the system may comprise a considerable number of branch oflice but since each may be similar to station No. 1, only one station is shown in detail, and the connections to other similar stations indicated in the'drawings. For example, the system may be used for interconnecting a plurality of branch retail stores in one city with the main or principal store in that city and through intercity trunks to headquarters or general oifices in a remote city.

In the embodiment shown, the lin Ll terminates at the main office or store in a jack J l and a receiving line relay II." The jack J l is provided for the purpose of effecting a connection to station No. 1 for a message from the'main office or an incomin circuit, and similar jacks J3, J 4 et cetera, at the same switchboard are provided for connecting to other stations. The relay I I, which may be a polar relay, responds to certainmes- 'sage signals received from station No. land is arranged to control a printer-perfo'rator PP, Fig. 2, to store the received message signals in the form of perforated tape for transmission to the remote office. The associated tape transmitter TT controlled by the tape 32 from the perforator is arranged after connection has been made to an idle line or channel, such asthe line L2, to repeat the stored signals to a receiving printer or reperforator (not shown) in the general ofiices.

The circuit of relay l I can be traced from negative battery through the winding 1 of said relay, normally closed contacts associated with the tip conductor'of jack J l', the right hand winding of marginal relay l2 which is adjusted so that it does not operate on normal line current, the line LI,

the normally closed contacts of the calling keys l3 and 14, the line relay I5, the keyboard contacts of the printer l0, and the winding of polar relay [6 to ground. The winding of relay I6 is poled to operate its armature to the left as shown when the linecircuit is connected to negative battery at the main ofilce, thereby maintaining the circuit of the supervisory lamp, I! open until connection is made to positive battery, as will be described below.

At station No. 1 the contacts of the line relay l5 are arranged to control the printer magnet of the printer l0 as shown, and also arranged to enerinvention may be used where a number of stores or factories are to be provided with facilities for" communicating with each other and witha 1 6 mote headquarters or general office, and. is of particular advantage where the majority of calls" from a group of branch stores or stations are d rected to the general office. One ofthev trunkchannels from the group of branch stations to the remote station or headquarters is indicated at L2, Fig. 2-. In order to facilitate the transmission of messages over these trunk channels which form the greater partof the 'traflic from the branch offices,- the systemembodying the" invention rearranged t'o p'i'ck up am idle trunk; channel for each call and repeat the message to the remote station without any necessity: for: manual supervision or switching of the? calls at the local main office where the trunk circuits or channels such asLZ unrminate. The automatie'repeating and the connected line or channel, such as the line. L2, "to transmit from the tape transmitter TT whenevera message is stored in the tape 32 and a line has been connected to said transmitter in response to the call. A finder switch individual to the line L2 is provided for picking up calls and connecting the same to said line or channel whenever it is idle. This finder switch comprises the Wipers 34, 35" and 35' and a stepping magnet 31, a similar switch being provided for each of the lines or channels to the remote station or headquarters.

Assuming that a message is to be transmitted from station No- 1 to the remote station or headquarters" over 'one of the intercity trunks, such as L2, in response to the operation of thekeyboard of the printer Hi the receiving relay ll of ol message'sat azlocal trunk. terminal'ofli'ce without supervision may, however, be'elfected over a local; circuit or any desired preselected channel, the deslgnationof the channeltL2 a's' given above beingtmerelyillustrative;

The relay H: is normally responsive-to line signals: from the printer [0 at the branch oflice or station: No; I and a "busy lam Zl is connected to the spacing contact thereof to dash; durin transmission from said. station. The marking contact of? relay H is arranged to operate the line relay 25 and the clutch magnet 28 of the distributor: associated. with 01: forming apart of the printer-perforator PP; Theclutch magnet 2510f the distributor is normally energized during. the rest or markingcondition of the relay H and responds to the first spacing: or start signal to release the cam shaft of the: distributor, thereby together with the contactsof the line relay 25 controlling the five selector magnets 2!- ofthe printer perforator PP, as: well: known to those skilled in th'e'art- The printer p'erforatorPP may be of any' conventional type, such as that shown, for example; in. the patent to Dirkes' and Wentworth, No. 2,143,828, granted January 10, 1939, except that it is provided' with contacts28 which close: on receipt of a blank or all-spacing code combination. The contacts-associated with stop members of theperforator' disclosed-in the Dlrkes and. Wentworthpatent which are closed upon the receipt ofa'particular code combination could beapplied to the stop member'of' the=blank selectiorrif the sixth pulse cut-out was omitted, but .shonldi preferably be arranged: toclose only moit under the-joint control-of the tape lever 33 the local main oflice controls the printer-perforator PP to record the message and perforate tape in accordance with the message signals from theprinter l0: Each of the successive messages le s-paced" by one or'more"blanks in the tape 32 in: a manner that will be'expl'ained below. The blanks in the tape at the transmitter will'cause the closure of the contacts 29, thereby: energizing relay 40 so long as blanks are'fedthroughi the tape: transmitter. The circuit for operating; the clutch. magnet 3i of the transmitting distributor may be traced from battery through the-winding of said clutch magnet 3|, the lower break; contacts of the tape lever 33, the right. hand armatu're and. back contact of slow-release' relay H,

and theleft hand armatureand-rbacle contact of slow-release relay 4% to" ground. The: operation .of: the distributor closes the circuit of the'stepping magnet of the tape transmitter '13?- through the right hand armature and back contact of relay 42- and the left hand contacts of the distributor tostep't'he blanks in th tape through the transmitter.

As soon as the first character ofthe message reaches the feeler pins ofthe tapetranemitter and the contacts 29- of the tape transmitter are opened; relay- 4!! becomes-deenergized. A-circuit is now'closed from ground through the second contacts 44 of the distributor (which are timed to close at the end of thefirstpulse and open attheend of the fifth pulse), the: circuit further including the armature and back confact of: relay M1, the winding of relay 4.1 and the left hand outer armaturev and back contact of relay 4!), whereupon relay 42 becomes energized,

opens the circuit of the steppingv magnet of the tape transmitter to prevent th first character of the message from being stepped through the transmitter before a line is connected thereto and prepares another circuit for relay'42 through the inner left hand armature and front contact thereof and the winding of relay 4'8. The operation of relay'42 also opens the circuit of the clutch ma net 3| of. the distributor at the left hand outer armature and back contact thereof to stop the distributor until the line circuit has been connected. r

Iftheline L2 is idle, the finder switch: willbe operatedfto'connect the tap'e'tra'nsmitter T1 and associated distributor individual to branch station No. I to said line circuit. When the contacts 44 of the distributor open to rem'oveground from the-above described operating-"circuit of relay 42, the last-mentioned relay locks up in serles'with relay 46 and said relay 46 becomes energized. The energization of relay 46 closes the circuit of the supervisory lamp 59 to-indicate that a mes"- sage is waiting from branch stationlfilo; 1. The

energization of relay 46 also closes a circuit from ground through its inner armature and front contact, the right hand outer armature and back contact of relay and the Winding of relay 52 to battery, whereupon relay 52 becomes energized. It will be understood that a system em. ploying a series of finder switches and control means therefor arranged to connect successive calls to idle lines or channels is not new, and any conventional arrangement of suitable character may be utilized. The control circuit is, therefore, not fully illustrated but is only indicated in sufiicient detail to provide a clear understanding of the invention.

As shown, relay 5| becomes energized when the line circuit is seized by a call and, if the line L2 had already been busy when relay 46 became energized as described above, the initiate circuit would have been extended through the right hand outer armature and front contact of relay 5| to relays 5|a and 52a associated with the second channel, as indicated. As many channels as are necessary to handle the traffic may be provided in this manner to connect an idle channel to each successive call. The energization of relay 52 as described closes the stepping circuit of the finder switch which may be traced from battery through the interrupter contacts 54, the winding of the stepping magnet 3'! of the finder switch, the

outer armature and front contact of relay 52,

the right hand armature and back contact of relay 53, and the switch wiper to the grounded bank contacts associated with said wiper and representing the lines which are not calling or which have been previously connected to a trunk chan- I nel. In this manner the finder switch is stepped to the terminals of the calling station where the above-described stepping circuit is interrupted at the contacts of relay 46 and the switch wipers 34, 35 and 36 stop as shown on the first contacts representing station No. 1. Relay 53 is now en-- ergized through the armatures and front contacts of relay 52 in series with the low-resistance stepping magnet 31, but the current in said circuit is insufficient to operate the stepping magnet. The energization of relay 53 grounds the multipled bank contacts of the other finder switches through the wiper 35 so that the terminals of station No. 1 test busy to the other finder switches. The energization of relay 53 also closes the circuit of relays 5| and 45 through the switch wiper 36 to connect the line circuit from the transmitter contacts through the make-before-break contacts of said relays to the line L2.

The energization of relay 5| as described transfers the initiate circuit to the next channel so that the next call will be picked up by the second channel. Relay 53 is maintained energized when relay 52 becomes deenergized through a circuit including the inner right hand armature and front contact of relay 5|, the last mentioned contact being adjusted to close before the circuit of relay 52 is interrupted at the outer right hand armature and back contact of relay 5!. The energization of relay 45 opens the above described circuit of relays 42 and 46, but relay 45 looks up through its inner left hand armature and front contact before slow-release relay 42 releases its armatures.

Upon the deenergization of relay 42 the above described circuit of the clutch magnet 3! of the distributor is reclosed at the outer left hand armature and back contact of relay 42. The cyclic operation of the distributor steps the tape transmitter TT to transmit the message char- 'acters perforated in the tape 32 to the line L2,

the transmitter remaining connected to the line until the end of the message. At the end of the message the operator at station No. 1 sends an end-of-message signal consisting of a blank or all-spacing code combination. The reception of the blank end-of-message signal by the printer perforator PP operates relay through the closure of the blank-reading contacts 28. If no further transmission ensues immediately from the printer ID at station No. l, relay 25 remains en ergized and holds open the left hand winding of relay 55 which is wound in opposition to the right hand Winding. Under these conditions relay 55 remains locked up through its right hand armatureand front contact, and closes a circuit through its left hand armature and front contact to the make contacts of. the tape lever 33. If the tape transmitter TT is able to transmit before another message is started, enough of the previous message so that the tape loop between the perforator and tape transmitter becomes taut, the raising of the tape leve 33 closes the circuit of relay 56 to cause feed-out of blank tape sufficient to enable the last message character perforated by the printer-perforator to reach the feeler pins of the tape transmitter, for example, as disclosed in the patent to Hoover, No. 2,252,852, granted August 19, 1941, in which case the clutch magnet I86 of the aforesaid Dirkes et a1. Patent 2,143,828 would be controlled in'the manner of the punch magnet 36 of the Hoover patent. Thus, the tape feed-out which is controlled jointly by the tape lever 33 and relay 56 will not occur until the end-of-message signal has been received by the printer perforator. Furthermore, if another message is started before the tape becomes taut, the release of relay 25 in response to the spacing signals of the code combinations representing the message characters causes current to flow through the left hand Winding of relay 55, and said relay releases its armatures to prevent the perforation of blank feed-out combinations before the end of the succeeding message, even though the tape again becomes taut between the perforator and the tape transmitter. Thus the perforation of blanks to space separate messages occurs automatically but only after the reception of a blank end-of-message signal.

Transmission continues from the tape transmitter TT over the line L2 until the blank endof-message signal reaches the feeler pins of the tape transmitter to cause the closure of the contacts 29 and reenergize relay 40. Upon the subsequent closure of the contacts 44 of the distributor while the contacts 29 remain closed, a circuit is closed through said contacts, the armature and front contact of relay All, the winding of s10W.

release relay 4 I, and the left hand outer armature and front contact of relay 45, whereupon relay 4| becomes energized and closes a locking circuit for itself through its left hand armature and front contact and winding of relay 41 to ground. The energization of relay 4| opens the above described circuit of the clutch magnet 3| of the distributor to stop transmission after the. blank end-ofmessage signal has been sent and stepped out of the tape transmitter. When the contacts 24 of the distributor open, relay 4? becomes energized and opens at its armature and back contact the above described circuit of relays 45 and 5|, thereby restoring the control circuits to their normal or initial condition. Upon the release'of the armatures of slow-release relay 4|, the circuit of the clutch magnet 3| of the distributor is reclosed if there is a loop of tape between the periorator and the tape. transmitter to permit the closure of the lower contacts of the. tape. lever 33, thereby stepping the. blank tape; through the tape trans.- mitter TT. Each successive message will normally be transmitted in this manner from the printer ill over the trunk circuit. L2; or over one of the other trunk circuits if this circuit is busy. Similarly, the finder switches associated with. the trunk circuits will pickup the: calls from other stationsv similar to station No. 1, each of said other stations being equipped with storage and repeating equipment similar to that shown and connected to other bank contacts of the finder switches individual to the respective trunk. circuits.

If, on the other hand, branch station No. 1 desires to transmit a message to the local oilice or main store at which the trunk circuits terminate, the operator momentarily opens the key M in the line circuit before transmitting the message. When the key M is actuated, the armature ofthe relay H- moves into engagement with its right hand or spacing contact, thereby short-circuiti'ng the winding of slow-release relay 58 which isinormally continuously energized through the series resistors 5.9 to battery. The slow-release relay 53 does not respond to the short spacing: signals of the code combinations representing message characters durihgtransmission over the trunk channel L2 as described. above. However; it responds to the long circuit interruption produced by the opening of the key I4, energizes the slow-release relay-S to render the printer perforator inoperative and closes the circuit of relay 613 and of the call lamp 6 3. Ifhe latter circuit may be traced from battery through the winding'of relay 63, the call lamp 6 1, the outer armature and back contact of relay -3 and the middle contacts'of the jack J l to ground. Upon the energization of relay 63.,

a locking circuit for said relay that isindependent of the contacts of relay 58* is closed through the inner armature and front contact thereof; and the call lamp 64 remains lighted after the key l4 has been reclosed. In response to the lighting of the call lamp 54 the attendant at the main store or oiiice inserts the plug 66 into: the jack J 'I, to connect the local printer Glto the calling line Liz. The insertion of the plug 66 into: the jack J'l opens the above described locking circuit of relay 63 to extinguish the call lamp 64 and also opens at the lower contactsof the jack M the circuit to the relay H, so that the trunk repeater equipment will not respond to the message signals from station No. 1.

W the Plug 66 is inserted in the jack J l, a circuit is also closed-from ground through the winding of relay 68; the tip contacts of the plug 567 and ofthe jack J l= and the winding of relay H to negative battery, whereupon relay 68 becomes energized and armature of relay H is held on the marking contact; The energization of relay 68 closes the line circuit including the sleeve contactsof the jack SH and plug 66 through the right hand armature and make-before-break contacts of relay 8B, winding. of the line rela 5!), keyboard contacts of the printer 6! and the normally closed contacts. of the jack J! to battery. Thus the printer 61 is conditioned fortwo-way communication with the printer H1 at station No. 1.

When the printer 61' is, plugged into the jack J I in. response to the call from branch station No. 1 as. described, the connection of the line L! to negative battery at the relay H is changed to the connection to positive battery at the jack J2 associated with the. printer 6?. The reversal of polarity of the batten on the line Li causes: the polar relay H3 at station No. 1 to actuate itsarmature into engagement with the right hand contact thereof, thereby closing a circuit through supervisory lamp I! to indicate at station No. 1 that a connection has been made to the main office printer 6? and transmission may be commenced.

As long as transmission continues from station No. l, the busy lamp H flashes since the; circuit of said lamp is intermittently closed through the armature and back or spacing contact of the line relay 89 which responds to the received code signals. A slow-release relay '12 is also provided which is maintained normally energized through the circuit including a resistor 13. At the end. of the message, the attendant at station Not 1 opens the key M and the consequent deenergization of relay 69 short-circuits the resistor 13 to deenergize relay T2. The disconnect lamp H is thus lighted to indicate to the operator at the main ofiice that the connection should be pulled down.

If station No. l desires to transmit a message to station No. 2, which may be a warehouse pro vided with a printer without a keyboard. for receiving messages from any of the local stores or branch stations, the key I3 is actuated to connect line LE to a source of positive battery and thereby increasethe line current sufiiciently to operate the marginal relay 12. Upon the euergization of relay 2 a locking circuit is closed through the left hand locking winding thereof, the call lamp H, the left hand armature and front contact of relay it and the outer armature and back contact of relay (3? to ground at the contacts of the jack J i. The lighting of the call lamp Ti indicates to the attendant at the main oihce or store that the branch station No. l desires a connection to the warehouse or station No. 2. Thereu-pon the attendant plugs in the circuit to station No; 2 by inserting the plug 78 in the jack J t, the control equipment associated with the plug "i8: being sim-- ilar to that associated with the plug 68. Thus the insertion of the plug 18 in the jackJl reverses the-pclarity of the line Li tolight a supervisory lamp I? at station No. l andindicate that the connection has been set up.

Other calls such as those originating at the headquarters or general offices, for example. and received over incoming trunk circuits-may also'be connected by'the attendant at the main store to any desired one of the branch ofiices or to the local printer through jacks J l to M. One such incoming trunk is indicated by the repcrforator 39, which represents the termial of any incoming trunk or channel, audits associated plug 81- for repeating the signals received over said incoming channel to the printers accessible through the jacks J l to J4.

The reperforator may be similar to the printer-perforator PP, Fig. 2, and provided with the usual tape feed-out mechanism; The associated tape transmitter TT is provided with bla'ni;- reading contacts 3-2 which are closed; upon the receipt oftheblank end-of-message signal.

The operation of the storage and repeating equipment including the perforator 80 and its associated tape transmitteris generally similar to that of the storage and repeating equipment shown in- Fig; 2 and described above except that the operation of the tape transmitter is initiated when it is plugged into the jack containing. the terminals of the wanted line. Upon the. receipt of the message over the incoming trunk circuit, the lengthening of the tape loop closes a circuit through the lower contacts of the tape lever 83 for energizing the clutch magnet 84 of the distributor. When the first character of the received message reaches the feeler pins of the tape transmitter TT, the contacts 82 open and relay 85 connected to said contacts becomes deenergized. Uponthe closure of the timing contacts 86 of the distributorat the end of the last blank code combination used for spacing successive messages, a circuit is closed through the armature and back contact of relay 85, the winding of slow-release relay 8'! and the left hand armature and back contact of relay 88 to battery, whereupon relay 8? becomes energized. The energization of relay .8! closes a circuit through its middle armature and front contact for lighting the call lamp 89 to indicate to the attendant that a call is waiting to be switched by the plug8l. Assuming that the call is for station No. has shown by the address on the tape, the insertion of the plug 8! in the jack J closes a circuit from ground through the winding of relay 88, the tip contacts of the plug 8| and jack J and the winding of relay II to energize relay88, to open the circuit of relay 8'! and thus extinguish the call lamp 89-. The deenergizatio-n of relay 81 recloses circuits through the left hand and middle armatures and back contacts of said relay for energizing the clutch magnet 84 of the distributor and the stepping circuit of the stepping magnet of the tape transmitter TI. The operator is able to determine the idle condition of the wanted station by observing that the busy lam 2| i not flashing, as would be the case if a message were being transmitted from thestation No. 1. At the end of the message, the end-of-message signal energizes relay 85 upon the closure of the blankreading contacts 82 at the same time that contacts 85 are closed. Thereupon a circuit is closed from ground through the timing contacts 86 of the distributonthe armature and front contact of relay 85, the winding of relay 9| and the left hand armature and front contact of relay 88 to battery, whereupon relay: 9| becomes energized. The energization of relay 9| closes through its left hand armature and front contact the circuit of the disconnect lamp 92 to indicate to the attendant that the message has been completed; and

- When the plug 8| is withdrawn from the jack,

relays 88 and 9| become deenergized, thereby restoring the cord circuit to normal in readiness for another call.

In the event that the call received over the trunk circuit on the perforator 80 is destined for a local or main office printer 61, the plug 8| is inserted in the jack J2, thereby extending the transmitting circuit from the tape transmitter TT through the right hand armature and front contact of relay 88, the sleeve contacts of the plug 8| and jack J2 and. the upper make contacts of the jack J2 to the keyboard and line relay 69 of the printer 61 and the message is recorded on said printer in the usual manner.

It will be seen that in accordance with the invention a system is provided for switching messages from a number of branch offices or stations to a local printer or to outgoing trunks or other branch offices and for switching calls from incoming trunk circuits either to a local printer or any desired one of the branch oiiices or stations. Furthermore, if the greater part of the traffic comprises messages from the several branch oflices for a single outgoing circuit, such as an intercity trunk circuit to a remote headquarters or ofiice, these calls may be made and transmission completed without any manual supervision or switching at the local main otfice. While specific apparatus is described, such as tape perforating and transmitting mechanism for storing and repeating message signals, it will be obvious that other types of control apparatus and signal storage and repeating mechanism may be employed instead of that illustrated for the purpose of explaining the invention. Various modifications in the specific circuits and control mechanism shown will occur to those skilled in the art andmay be made without departing from the scope of the invention as defined in the appended claims.

We claim:

1. A telegraph exchange system comprising a main office, telegraph trunks or channels terminating at said oflice, a branch office from which the majority of the messages are to be sent over a particular one of said trunks or channels, a printer at said branch ofiice, means including signal-repeating equipment and automatic switching apparatus at said main office responsive to predetermined incoming signals from the branch office for normally repeating all message signals transmitted from said printer over said particular one of said trunks or channels to a preselected destination and other switching means at said main office to disable said signal-repeating equipment and enable transmission of a message from said printer over another of said trunks or channels. I

2. A telegraph exchange system comprising a main office, telegraph trunks or channels terminating at said ofiice, a branch office, printing telegraphequipment at said branch oifice, means including automatic switching apparatus at said main ofilce responsive to predetermined incoming signals from the branch ofiice for causing messages from said branch oifice normally to be transmitted over one of said trunks or channels to a preselected destination and operator-controlled means at said main ofiice to disable the normal transmission from the branch ofiice over said one of said trunks or channels and connect the printing telegraph equipment at said branch office to any desired one of a plurality of other trunks or channels terminating at the main office.

3. A telegraph exchange system comprising a main ofiice, telegraph trunks or channels terminating at said office, a branch office, printing telegraph equipment at said branch ofiice including means for transmitting message printer signals and directing signals, means including automatic switching apparatus at said main ofiice responsive to predetermined directing signals from said branch ofiice for causing messages from the branch office normally to be transmitted over one of said trunks or channels to a predetermined destination without manual supervision or manual switching at the main oflice, signaling means at the main office responsive to other directing signals from said branch oflice to indicate that the branch office is to be connected to certain others of said trunks or channels and manually operable switching means at the main olfice for connecting the branch office to said other trunks or channels.

4. A telegraph exchange system comprising a main 'ofiice, telegraph trunks or channels terminating at said office, a branch oflice, printing telegraph equipment at said branch oilice, sign-alstorage and repeating equipment at said main office individual to said branch office and one of said trunks or channels and normally operative to repeat messages from the branch oflice over said one of said trunks or channels, signaling means at the main o'fiice to indicate when the branch ofiice desires to transmit over another of said trunks or channels and means to connect the branch ofiice to the desired other trunk or channel.

-5. A telegraph exchange system comprising a main office, telegraph trunks or channels term-inatingat said ofiioe, certain cf said trunks or channels com-prising a group extending to the same destination, a plurality of branch o'fiices, repeater equipment at said main oflice for each of said branch oflices comprising a tape =reper-forator and associated tape transmitter individual to said group of trunks or channels, means for seizing an idle channel and connecting it to the repeater equipment of a calling branch p'fiiee in response to the transmission of a message to the main office from the las't 'mentioned branch office and means at the main omcefor connecting the branch offices to others of said trunks or channels, when desired.

-6. in telegraph exchange system comprising a main oflice, telegraph 'trun'ks or channels terminating at said 'oflice, a pluraltiy of branch ofiices provided with printing telegraph equipment, signal-st'orage and repeatingequipmentat said main office normally connected *to the printing 'telegraph equipment at the respective branch oflices and arranged to repeat message signals overeertain of said trunks or channels, signals at -the main "ofiice for designating a desired trunk or channel difierent from that normally available to the branch oflice mak ing a call, :mean's for operating said signals from the branch oflicesand means at the main 'ofice to reconnect a calling branch-ofiice to a wanted trunk or channelin accordancewith saidsignals.

A telegraph exchange system comprising a main ofiice, telegraph trunks or channels terminating thereat, a plurality of branch offices, printing telegraph equipment at said ofiices including a local printer at the main office, means including automatic switching apparatus at said main office responsive to predetermined incoming signals from the branch oifice whereby transmission is effected from the printing telegraph equipment at the branch oifices over one of said trunks or channels without manual supervision or switching at the main oflice, means for signaling the main ofiice when a branch ofii'ce desires to transmit a message thereto which is not to be sent over any of said trunks or channels and means to connect said local printer at the main oflice to acalling branch office.

8. In a telegraph exchange system, a main office, a branch ofiioe including atelegraph printer, a line -'circu-it. connecting said oflices, a first key at the branch o'flice for interrupting the line cirwit, a second key at the branch ofiice for altering the electrical potential of the line circuit, a plurality of supervisory signal devices at the main oflice selectively controlled by said keys over the line circuit and respectively indicating different desired connections to be made to the branch office line, means including a slow acting relay operable upon said interruption of the line circult by said first 'key for a predetermined length of time for energizing one of said signal devices, and means including a relay responsive to the changed potential established by said second key for energizing another of said signal devices.

9-. In a printing telegraph exchange system, a main oflice, a branch ofiice including a telegraph printer, a telegraph circuit connecting said offi'ces, a plurality of line-designating signal devices at said main office controlled from said branch ofiice overs'aid circuit, said signal devices respectively indicating different desired connections to be made to the branch ofi'ice line, and go-ahead and busy" signal devices at said branch ciffice also controlled over said circuit.

EUGENE A. 'DEMONET.

B. BLANTON. 

